Math and Stablization

Hello again, all. So I was lucid last night (third night in a row, really excited about that). I have been having a bit of trouble with dream stability, so I learned so stabilization techniques from this forum and other places. One of them mentioned to do math to get your logical brain active. I had done it before and it helped then. So any who, after I became lucid last night I did other stabilizer techniques (sensory awareness, hand rubbing) which helped a lot, scene really popped in to focus. However, when I started doing math, the dream de-stabilized and became rather blurry. I lost lucidity soon after. I was wondering if anybody else used this to stabilize, and if so, does it work for you?
The second question involves continuous lucidity. What are some tips for extending my periods of lucidity (outside of stabilization, obviously)? My problem is no longer that I wake up on lucidity, but instead that I slip in and out of lucidity a lot. How do I keep it one long lucid dream instead of a bunch of 2-3 minute periods?

I guess the math thing would work the more simpler the question is. Thoughts require some energy so you don't want to be thinking too much, I guess maybe doing a times table in your head would work alright?